This invention relates generally to material processing, and more specifically to cleaving material work pieces through crack propagation.
Semiconductors are an important and valuable material in the electronics and photovoltaics industries due to their unique properties, versatile applications and now widespread use. Semiconductors are often used in wafer form. However, current wafer fabrication methods are wasteful and can result in up to 50% material loss. Mechanical wire sawing of large semiconductor ingots/blocks into the thin wafer form is the industry standard, but kerf loss caused by the saw wire is inevitable. Sawing also damages the surface of the resultant wafers, leading to a need for damaged material removal and subsequent surface finishing to achieve the high-grade wafers that are required for many applications. Polishing and mechanical grinding are often used to finish the surfaces of wafers, and these post-processing steps remove even more material from the wafers, further increasing the overall material loss. High material loss during the manufacturing of semiconductor wafers results in less semiconductor material that can be used for applications and higher cost per wafer.
Cleaving material work pieces via crack propagation is a promising alternative to current wafer processing methods because it results in little material loss. Further, it is seen that this type of cleaving results in higher quality wafer surfaces, potentially reducing or eliminating the need for post-processing steps to achieve high-quality surface finishes. However, producing wafers through such cleavage methods comes with challenges of its own. Particularly, controlling the propagation of the crack with the precision that is necessary to create high-quality wafers can be difficult. Additionally, current processes exploring this method have low throughput and high cost and are thus not suitable for mass production.